Many different devices offer microphones for a variety of different purposes. The microphones may be used to receive speech from a user to be sent to users other devices. The microphones may be used to record voice memoranda for local or remote storage and later retrieval. The microphones may be used for voice commands to the device or to a remote system or the microphones may be used to record ambient audio. Many devices also offer audio recording and, together with a camera, offer video recording. These devices range from portable game consoles to smartphones to audio recorders to video cameras etc.
When wind or other air movement impacts a microphone, a noise is created which may impair, overwhelm, or render unintelligible the rest of the audio signal. A sound recording may be rendered unpleasant and speech may not be recognizable for another person or an automated speech recognition system. While materials and structures have been developed to block wind noise, these typically require bulky or large external microphones which may be impractical, inconvenient, or impossible to use with many devices. There are also software-based wind noise reduction systems that use complex algorithms to isolate the wind noise from other sounds and then reduce or cancel the wind noise.
Wind noise reduction techniques tend to be complex because wind noise is very non-stationary and, if there are multiple microphones, the noise will be different at each microphone. Wind noise represents a special class of noise because it is directly generated by the turbulence of a wind stream around the device. The turbulence will be different at different positions on the device and change quickly over time.